I was in my high school rugby team. I was pretty sure by this point that I was gay, and sometimes struggled a bit to keep control of my erections in the showers. The rugby coach was a great guy, and all the guys liked him.
This one afternoon I'd had to get out of the showers first due to a rising cock watching Matt, one my team mates, rub soap into his balls and cock. I threw a towel around myself as I left the shower room but my cock was now sticking straight out ahead of me and I bumped into the coach in the corridor. He was nonchalant and ignored my throbbing erection, but three minutes later asked me to come into his office, which was directly off the locker room. I had boxers and a t-shirt on by this point, but I did so.
Once he'd shut the door he asked me if I wanted to talk about anything with him. When I didn't reply he clarified and said he'd noticed my struggle and asked me if I was attracted to the other boys. I mumblingly confided that I was, wondering if he was going to kick me off the team or something.
But he didn't, he talked to me for ages, about how it was okay, normal, etc etc, and after he'd got me smiling again he asked me if I'd ever had any experiences with another guy. I said no. He asked me if I would like to, and as he asked me he reached down and rubbed my cock through my boxers. I swallowed and nodded and closed my eyes as he began to rub. After a few minutes he told me to stand up and he bent me over the desk. For a second I thought he was going to have sex with me, but he kept his hand wrapped around my cock and I felt his own erection against the back of my boxer shorts. He'd pushed his trackies down to his knees, and for a few minutes he dry humped my backside while jerking me off. I exploded, great streams of cum soaking my boxers and his desk, and then I felt something soaking through onto my skin and realised he'd cum all over the back of my boxers too. We were both panting and I stood up and thanked him and left.
We had a lot of sessions after that, but that first experience will always be special to me...